In designing air-conditioning systems for large-scale indoor spaces, it is important to predict the air velocity and temperature distributions in such spaces to enable indoor climate to be controlled effectively. The indoor climate can be predicted by two numerical simulation methods: one is a rough study by using a macroscopic model and the other is numerical simulation based on a turbulence model. Each method has its own limitations.
The present paper reports on tracer gas measurements performed in five large buildings during normal operating conditions. In all buildings air was supplied through ceiling diffusers and returned through a ceiling plenum. The measurements were taken during summer with the systems in cooling mode, i.e. the supply temperature was lower than the room temperature. The global air change effectiveness and the occupied zone average air change effectiveness were calculated based on the age-of-air concept.
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